Expansion anchor stud

Abstract

An expansion anchor stud comprises an expansion anchor for gripping a hole in a surface, an axially-aligned, externally threaded stud of substantially the same outside diameter as the anchor and engaging the distal end of the anchor, and an axially-aligned bolt extending through a hole in the anchor and engaging the stud. A head on the proximal end of the bolt abuts the proximal end of the anchor, and external threads on the bolt engage internal threads in a hole extending through the stud. The anchor is expanded by a tool inserted into the distal end of the hole in the stud to engage the distal end of the bolt and rotate the bolt relative to the stud, thereby axially compressing, and hence expanding, the anchor. The distal end of the stud extends, in use, through a hole in a panel being mounted to the surface so that a nut may be threaded onto the external threads of the stud to secure the panel to the surface. The distal end of the bolt is provided with a recess, slot, crossed slot or the like, for receiving an Allen wrench, the blade of a screwdriver, the tip of a Phillips head screwdriver, or the like, respectively. The expansion anchor is preferably of the double expansion type having a first expansion member disposed at its distal end and a second expansion member disposed at its proximal end, and the proximal expansion member may be unitary with the head of the bolt.

I claim: 
     
       1. An expansion anchor stud comprising: a threaded bolt having a shank of a first diameter and a head of greater diameter than the shank, the shank of said bolt having an externally threaded portion;   an externally threaded stud of a second diameter, greater than the first diameter and having a hole therethrough for receiving the shank of the bolt, said hole through the stud having a threaded portion for engaging the externally threaded portion of the bolt; and   an expansion anchor having an outside diameter substantially equal to the second diameter and having a hole therethrough for receiving the shank of the bolt;   wherein the shank of the bolt extends through the expansion anchor and is rotatable relative to the stud to compress and expand the expansion anchor.   
     
     
       2. An expansion anchor stud according to claim 1, further comprising: means for rotationally interlocking the stud and the expansion anchor.   
     
     
       3. An expansion anchor stud according to claim 2, wherein: the means for rotationally interlocking the stud and the expansion anchor comprises axially extending prongs on the proximal end of the stud and corresponding prong-receiving notches on the distal end of the expansion anchor.   
     
     
       4. An expansion anchor stud according to claim 2, wherein: the expansion anchor is of the double expansion type having a first expansion member disposed at its distal end and a second expansion member disposed at its proximal end, and the first expansion member is unitary with the proximal end of the stud.   
     
     
       5. An expansion anchor stud according to claim 1, wherein: the distal end of the bolt is provided with means for receiving a tool for rotating the bolt relative to the stud.   
     
     
       6. An expansion anchor stud according to claim 5, wherein: the means for receiving a tool is a hexagonal recess for receiving an allen wrench.   
     
     
       7. An expansion anchor stud according to claim 5, wherein: the means for receiving a tool is a slot for receiving the blade of a screwdriver.   
     
     
       8. An expansion anchor stud according to claim 5, wherein: the means for receiving a tool is a crossed slot for receiving the tip of a Phillips head screwdriver.   
     
     
       9. An expansion anchor stud according to claim 1, wherein: the expansion anchor is of the double expansion type having a first expansion member disposed at its distal end and a second expansion member disposed at its proximal end, and the second expansion member is unitary with the head of the bolt.   
     
     
       10. An expansion anchor stud according to claim 9, wherein: the second expansion member is free to rotate relative to the remainder of the expansion anchor.   
     
     
       11. An expansion anchor stud according to claim 1, further comprising; means for rotationally interlocking the stud and the expansion anchor; and   wherein the expansion anchor is of the double expansion type having a first expansion member disposed at its distal end and a second expansion member disposed at its proximal end, and the second expansion member is unitary with the head of the bolt.   
     
     
       12. An expansion anchor stud according to claim 11, wherein: the means for rotationally interlocking the stud and the expansion anchor comprises axially extending prongs on the proximal end of the stud and corresponding prong-receiving notches on the distal end of the expansion anchor.   
     
     
       13. An expansion anchor stud according to claim 11, wherein: the expansion anchor is of the double expansion type having a first expansion member disposed at its distal end and a second expansion member disposed at its proximal end, and the first expansion member is unitary with the proximal end of the stud.